The utility of semi-automatic or automatic rifles can depend upon the physical size of the rifle, especially in military or law enforcement situations where space can be limited. For example, a longer rifle can be more unwieldy than a compact rifle within the cramped quarters of an armored vehicle, aircraft, or patrol car, making the transport, storage and maneuverability of the rifle cumbersome. Gunstocks often represent over one-third of the total length of any particular rifle, so the ability to fold the stock of a rifle against its remaining sections can significantly reduce the space required to store and maneuver the rifle.
Many types of folding stocks currently exist for most military-style assault rifles. See U.S. Pat. No. 7,162,822 by Heayn et al. among many others. Additionally, various types of collapsible or telescoping stocks are also currently available. However, a collapsible stock apparatus does not fully solve the size problem because that type of stock slides along a rifle's receiver extension, which typically contains the buffer and action spring used to actuate such rifles. Therefore, these devices can only shorten the stock, by a length that does not include the receiver extension, which can often account for one-third or more of the total length of the stock.
Alternatively, some folding stock adapters have been designed to allow fixed stocks the ability to fold. See U.S. Pat. No. 7,966,761 by Kuczynko et al. among many others. However, these existing folding stock adapters have been less than ideal; because certain parts of some military-style assault rifles, such as the action spring and bolt carrier, travel from the receiver of the firearm into the receiver extension, which is located within the stock of the rifle. Therefore, a folding stock adapter for such guns must be able to account for the weapon's bolt carrier, buffer and action spring when the weapon is either in a folded position or an unfolded position. The present workarounds for folding stock adapter have required reduced functionality in order to address this issue.
What is needed is a folding stock adapter for use with military-style assault rifles which can accommodate the standard bolt carriers, buffers, receiver extensions and action springs comprising such weapons, which can also allow the stocks of such weapons to be folded over against the remaining parts of the rifle to substantially reduce its overall physical size, allowing easier transport, storage and maneuverability in space restrictive conditions, while allowing the rifle to be quickly unfolded to function and fire normally.